Which is true?

"X extends Y" is correct if and only if X is a class and Y is an interface
"X extends Y" is correct if and only if X is a class and Y is an interface
"X extends Y" is correct if X and Y are either both classes or both interfaces
"X extends Y" is correct for all combinations of X and Y being classes and/or interfaces

Correct Answer: "X extends Y" is correct if X and Y are either both classes or both interfaces

Explanation:

A is incorrect because classes implement interfaces, they don't extend them. B is incorrect because interfaces only "inherit from" other interfaces. D is incorrect based on the preceding rules.

← Previous Question Next Question→

More Questions from Technology

class Hell { public static void main(String[] args) { Integer i = 42; String s = (i<40)?"life":(i>50)?"base":"ball"; System.out.println(s); } }
try { int x = Integer.parseInt("two"); } Which could be used to create an appropriate catch block?
Difference between Java Beans & Servlets?
Just by seeing the signature of the bean how can you specity whether it is a Statefull of Stateless Session Bean?
How are this() and super() used with constructors?
How do you decide when to use HashMap and when to use TreeMap ?
What is the Dictionary class?
What is the common usage of serialization? What exceptions occur during serialization?
What is the purpose of garbage collection in Java, and when is it used ?
When is the finalize() called ? What is the purpose of finalization ?

Discussion & Comments

No comments yet. Be the first to comment!

Join Discussion